Five tonnes of antibiotics used to combat disease in salmon

Five tonnes of antibiotics were used in Tasmania’s salmon farming industry to combat a severe disease outbreak, according to recent reports. The revelation came as the industry faced mounting pressure from environmental groups and regulators over its reliance on antibiotics, particularly florfenicol, which was temporarily banned by the federal authority. The data shows that between January and April 2025, nearly 15,000 tonnes of salmon died due to a bacterial infection, prompting urgent action from the sector.

The use of antibiotics reached a critical point when the salmon industry, led by Salmon Tasmania, was forced to apply for and receive an emergency permit to use florfenicol. This antibiotic, typically used in land-based farming, was approved for use in Australian waters in November 2024 after initial treatments with oxytetracycline proved largely ineffective against the disease. The decision followed a devastating second wave of infections that affected fish pens in south-east Tasmania, leading to significant losses in the industry.

The scale of antibiotic usage became apparent when the final figures were released, revealing that over 5,000 kilograms of florfenicol were administered during the outbreak. This number highlights the severity of the situation and the measures taken by the industry to mitigate the crisis. However, the use of the antibiotic was soon called into question when it was discovered that traces of florfenicol had been found in wild fish populations up to 10 kilometers away from the sites of application. As a result, the Australian Pesticides and Veterinary Medicines Authority (APVMA) revoked the permit in March 2025, citing potential risks to marine ecosystems.

Environmental advocates, including the Tasmanian Greens' representative Vica Bayley, expressed strong criticism of the industry’s actions. Bayley described the use of such large quantities of antibiotics as a “shocking indictment” of the industry’s practices and questioned the effectiveness of the approach. She argued that the method was not a sustainable solution and that the environmental impact should not be overlooked. The Greens have long pushed for the relocation of salmon farming operations onto land to reduce ecological footprints, emphasizing the need for more environmentally friendly alternatives.

In response, the salmon industry reaffirmed its commitment to responsible antibiotic management and outlined plans for a multi-strategy approach to fish health. This includes the continued use of antibiotics alongside vaccinations and selective breeding techniques aimed at improving disease resistance. John Whittington, CEO of Salmon Tasmania, stated that the industry is currently working on reapplying for a permit to use florfenicol, highlighting the complex regulatory landscape and the need for thorough assessments of safety and efficacy.

The incident underscores broader challenges facing aquaculture industries globally, balancing the need for disease control with environmental stewardship. The case in Tasmania serves as a cautionary tale about the potential consequences of antibiotic misuse and the importance of developing alternative strategies to ensure both animal welfare and ecosystem protection. As the industry moves forward, the focus will likely shift towards innovative solutions that minimize reliance on antibiotics while maintaining productivity and sustainability.